This invention relates generally to washing machines, and, more particularly, to methods and apparatus for controlling agitation time and agitation speed during agitation phases of wash cycles.
Washing machines typically include a cabinet that houses an outer tub for containing wash and rinse water, a perforated clothes basket within the tub, and an agitator within the basket. A drive and motor assembly is mounted underneath the stationary outer tub to rotate the clothes basket and the agitator relative to one another, and a pump assembly pumps water from the tub to a drain to execute a wash cycle. See, for example, U.S. Pat. No. 6,029,298.
Periodically as the washing machine is used, the agitator is actuated by a control mechanism and imparts an oscillatory motion to articles and liquid in the basket, thereby producing mechanical washing action and energy to clean articles in the basket. Traditionally, the agitator is actuated for a fixed time period and at a fixed, predetermined actuation speed or intensity during agitation phases of a wash cycle. For certain laundry loads, however, the agitation speed and/or the agitation duration may be excessive. Aside from energy considerations associated with unnecessary agitation, excessive agitation extends the time for the wash cycle to complete and can lead to excessive wear of laundered articles washed in the machine.